There are numerous diseases which can be treated successfully if detected early, but which can cause long term damage if not timely diagnosed and treated. Diseases such as vesicoureteral reflux can cause significant harm to an individual, but are not easily diagnosed without invasive procedures.
In vesicoureteral reflux bladder urine flows back up into the ureters and into the kidneys. The urine can cause kidney infections which can be painful. Moreover, repeated infections can cause long term kidney damage. While vesicoureteral reflux can be treated with medication or by surgical techniques, vesicoureteral reflux is difficult to properly diagnose.
Approximately 2% of all children at any one time have a urinary tract infection. When a child has had more than one kidney infection, it is desirable to determine if the child has vesicoureteral reflux. Two radiologic imaging studies are commonly utilized: voiding cystourethogram (VCUG) and a nuclear cystogram. A VCUG is performed in humans of all ages by first placing a sterile catheter in the patient's urethra and through the catheter instilling radiopaque contrast, such as Cystografin. The kidneys and bladder are observed during a bladder filling and emptying cycle using x-rays. The patient has an initial x-ray film taken, then an anterior-posterior film and then films in each lateral oblique. When voiding is initiated, fluoroscopy is utilized, and spot films are taken to document changes during voiding. This process has been necessary to evaluate bladder anatomy, function, and elimination and to confirm the existence of vesicoureteral reflux. After the first infection it is currently recommended that patients undergo a VCUG and a renal imaging study. However, doctors are sometimes reluctant to order the invasive VCUG until other infections occur. Of the VCUGs performed, approximately one of three patients will have vesicoureteral reflux. The reflux is graded and treatment is assigned on the basis of severity. About three-quarters of the patients are assigned to medical management and are screened with a VCUG each year until their reflux resolves. This averages about three years of waiting before resolution occurs. Patients who undergo surgical correction of their reflux also require a follow-up VCUG to evaluate the success of the procedure. Patients with enuresis either at night or during the day are evaluated with VCUGs on occasion. Since the test is currently invasive, it is withheld until the patients are older or unusual symptoms indicate its necessity. It will be appreciated that the VCUG procedure is uncomfortable and can be traumatic, particularly for children.
Likewise, various other conditions exist in which body fluids, such as urine or blood, improperly flow as a result of disease or dysfunction. For example, gastroesophageal reflux is common in young children. Other conditions involve disruptions in blood flow or myocardial function resulting from narrowing of the aorta, blood clots, or malfunction of the enterohepatic circulation or a portion of this system, e.g., the intestine, liver or gall bladder, or disruptions in flow of cerebrospinal fluid. Diagnosis of such conditions has often required invasive procedures, such as use of catheters or tubes.
Besides the diseases above, body tissues are subject to other abnormalities including cancer, scarring, inflammation and reduced function. One potential effect of the abnormalities includes abnormal tissue abnormally encouraging or restricting thermal spread. Thus, the improper flow of bodily fluids may be a condition that should be treated, or may be a symptom of a disease in need of treatment. Either way, prompt detection of such conditions would be beneficial.
There has been some discussion regarding administering microwave or ultrasound energy through an external energy source to warm a fluid in a target organ or tissue and detecting a warmed fluid distant from the target. (See, e.g., U.S. Pat. No. 7,271,245.) However, blind application of the thermal energy for a predetermined time may cause many problems, such as mis-targeting of the device, over or under heating of the target area, skin burns by mis-placement of the device and/or uncomfortable or damaging heating of the antenna itself against the patient.
There has also been discussion about a flexible microwave antenna array on a flexible circuit board. (See, e.g., U.S. Pat. No. 6,330,479.) However, sensing deep tissue temperature in a noninvasive manner can be difficult, as the emitted energy is small.
As diseases such as vesicoureteral reflux have relied on invasive and traumatic diagnosis procedures, a non-invasive and less traumatic diagnosis method and equipment would be desired. Moreover, a method for diagnosing or treating diseases with thermal energy which does not burn or otherwise discomfort patients would also be desirable.
Other methods of using radiometers and related devices in medical procedures are also desirable, as will be further discussed below.